No, the Aqueon 10 isn't adjustable. So the sponge helps reduce the flow significantly. My betta is free to swim pretty much anywhere now. You can still see the flow if he swims in front of the filter, but it doesn't shoot him across the whole tank now. I've only had it running for about 3 months or so, but I run the regular filter cartridge and the sponges and I've never had any problems with the pump overflowing. It also does seem to work better with the water level at the level of the sponge. As the water level drops you get more current from how far the water has to fall to hit the surface.

Not sure what the GPH is but its rated for up to a 20G tank.
Here is my actual aqueon 10.

I have some plants in front of it to help break up the outflow even more. When i do the WC's I refill it up to the filter foam baffle but within a week/wee and a half - the water level drops by about 1 inch. It amazes me how much the water evaporates out of the tank in lie a week!

Are the yellow sponges safe? You know the ones with the abrasive green side and soft yellow side? My mom got me a pack a while back but I never used them so I'm wondering if they are safe or not. I'm scared that they might be treated with bad chemicals or something like that....

are you talking about a kitchen sponge? Not sure if it has chemicals or not.
I would get aquaclear filter foam since it is ment for aquariums. Or any other brand of aquarium foam.
They aren't expensive - maybe $3 max depending on the size you get. You can cut them up if need be and they can squish into any size. I also have them inside my tetra 10i filters, not as a baffle but inplace of the filter pads.

Thank you for this baffle idea. I have a Dynaflo 10 in a 5 gallon tank, the water is
pristine, but the current was a bit too strong for comfort. I was lucky because the baffle on this filter doesnt not need any support or tying, it holds by itself